The present invention relates to devices for establishing plural connections between spaced-apart electrical conductors, e.g., between one or more bus bars in the recess of a terminal box and one or more strip-shaped conductors.
It is already known to provide an elongated conductor with several discrete clamping devices, each of which can selectively establish and/or break connection between such conductor and one or more bus bars. In conventional clamps, a slide is provided which has two clamping jaws and a screw extending therebetween. The slide is mounted on the contact rail of the clamp, with the clamping jaws positioned on opposing sides of the contact rail, and the slide can be shifted into and out of contact with a bus bar, which carries the power supply. If power supply is to pass from the bus bar via the clamp to the contact rail, the slide is moved into contact with the bus bar and "closed" by turning the screw so that the clamping jaws engage the contact rail and the bus bar and establish a connection therebetween. If the power supply to the clamp (and the units and devices connected to it) is to be interrupted, the clamping jaws of the slide are loosened by means of turning the screw and the thus "open" slide is shifted back out of contact with the bus bar, back into the housing of the clamp.
Attempts have been made to improve the ability to shift the open slide on the contact rail, e.g., by providing a plastic sleeve surrounding the clamping screw and mounting the sleeve on a ledge of the housing. However, this construction repeatedly results in tilting of the clamping jaws in various directions when shifting the open slide on the contact rail. This is because the clamping jaws in such construction still have a considerable degree of unrestrained movement when the slide is in an open position, i.e., the clamping jaws lie relatively loosely in the housing surrounding them. Moreover, the force necessary to move the open slide must be applied with the screwdriver which is used to turn the clamping screw, and because of the distance of the gripping location from the contact rail, the application of such force is difficult and further tends to cause tilting of the clamping jaws.
An additional disadvantage of prior art clamps has been their exclusive reliance upon the clamping screw to insure that unwanted connection between the contact rail and bus bar is avoided. If, when the slide is moved out of contact with the bus bar, i.e., back into the housing, the clamping screw is inadvertently not securely tightened, the slide may, upon jostling of the clamp, particularly when the clamp is mounted over the bus bar and the slide moves in an up and down direction, move into contact with the bus bar and charge the contact rail and associated unit or device. This can damage the unit or device and may even result in injury to the operator, repairer or installer
A still further disadvantage of prior art clamps has been that, particularly when the clamping jaws are hollow, the clamping jaws have a tendency to rotate about the axis of the clamping screw as the screw is turned to tighten the slide.